Methods for transmitting uplink signal and downlink signal, UE and base station

ABSTRACT

Embodiments of the present disclosure provide methods for transmitting an uplink signal and a downlink signal. A method for transmitting an uplink signal comprises detecting whether there is a beam failure; if there is a beam failure, determining at least one of whether there is a candidate downlink transmission beam(s) or candidate downlink transmission beam information; and transmitting a beam failure recovery request message to a base station, the beam failure recovery request message being used for informing the base station of at least one of whether there is a candidate downlink transmission beam(s) or candidate downlink transmission beam information. A method for transmitting a downlink signal comprises detecting a beam failure recovery request message, determining at least one of whether there is a candidate downlink transmission beam(s) or candidate downlink transmission beam information in the UE; and transmitting a feedback message corresponding to the beam failure recovery request message.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/971,679 filed on May 4, 2018, which is based on and claims priorityunder 35 U.S.C. § 119 to Chinese Patent Application No. 201710313292.8filed on May 5, 2017 in the State Intellectual Property Office of China,the disclosures of which are herein incorporated by reference in theirentirety.

BACKGROUND Field

The present disclosure relates to the technical field of signaltransmission, and in particular to methods, a UE and a base station fortransmitting an uplink signal and downlink signal.

Description of Related Art

The rapid development of information industry, particularly theincreasing demand from the mobile Internet and the Internet of Things(IoT), brings about unprecedented challenges in the future mobilecommunications technology. According to the ITU-R M. [MT.BEYOND2020.TRAFFIC] issued by the International Telecommunication Union (ITU),it can be expected that, by 2020, mobile services traffic will grownearly 1,000 times as compared with that in 2010 (4G era), and thenumber of user device connections will also be over 17 billion, and witha vast number of IoT devices gradually expand into the mobilecommunication network, the number of connected devices will be even moreastonishing. In response to this unprecedented challenge, thecommunications industry and academia have prepared for 2020s bylaunching an extensive study of the fifth generation of mobilecommunications technology (5G). Currently, in ITU-R M. [IMT.VISION] fromITU, the framework and overall objectives of the future 5G have beendiscussed, where the demands outlook, application scenarios and variousimportant performance indexes of 5G have been described in detail. Interms of new demands in 5G, the ITU-R M. [IMT.FUTURE TECHNOLOGY TRENDS]from ITU provides information related to the 5G technology trends, whichis intended to address prominent issues such as significant improvementon system throughput, consistency of the user experience, scalability soas to support IoT, delay, energy efficiency, cost, network flexibility,support for new services and flexible spectrum utilization, etc.

The performance of random access directly influences the user experienceof UE. In conventional wireless communication systems, such as Long TermEvolution (LTE) and LTE-Advanced, the random access procedure is appliedin many scenarios, for example, establishment of initial connections,cell handover, re-establishment of uplink connections, re-establishmentof RRC connections, or the like. And the random access is divided intocontention-based random access and contention-free random access,depending upon whether the UE uses the preamble sequence resourcesexclusively or not. Since a preamble sequence is selected from the samepreamble sequence resources during the attempt of establishment of anuplink connection by UEs in the contention-based random access, it maybe possible for a plurality of UEs to select a same preamble sequence tobe transmitted to the base station. Hence, a contention resolutionmechanism becomes an important research aspect of random access. How toreduce the contention probability and how to rapidly resolve contentionsthat have already taken place are key indicators that influence theperformance of random access.

The contention-based random access process in LTE-A includes four steps,as shown in FIG. 1. In the first step, a user randomly selects apreamble sequence from a preamble sequence resource pool and transmitsthe preamble sequence to a base station; and, the base station performscorrelation detection on the received signal, so as to identify thepreamble sequence transmitted by the user. In the second step, the basestation transmits a Random Access Response (RAR) to the UE, the RARcontaining an identifier of a random access preamble sequence, a timingadvance instruction determined according to a time delay between the UEand the base station, a Cell-Radio Network Temporary Identifier(TC-RNTI), and time-frequency resources allocated for the UE to performuplink transmission next time. In the third step, the user transmits aMessage 3 (Msg3) to the base station according to information in theRAR. The Msg3 contains information such as a UE terminal identifier andan RRC link request, wherein the UE terminal identifier is an identifierthat is unique to the UE and used for resolving contention. In thefourth step, the base station transmits a contention resolutionidentifier to the UE, the contention resolution identifier containing aUE identifier corresponding to a user who wins in the contentionresolution. The UE upgrades TC-RNTI to C-RNTI upon detecting itsidentifier, and transmits an Acknowledgement (ACK) signal to the basestation to complete the random access process and waits for thescheduling of the base station. Otherwise, the user will start a newrandom access process after a certain delay.

For a contention-free random access procedure, the base station mayallocate a preamble sequence to UE since it has known the identifier ofthe UE. Hence, the UE does not need to randomly select a sequence whentransmitting the preamble sequence, and instead, it uses an allocatedpreamble sequence. The base station will transmit a corresponding randomaccess response after detecting the allocated preamble sequence, therandom access response containing timing advance, allocation of uplinkresources and other information. After receiving the random accessresponse, the UE deems that the uplink synchronization is completed andwaits for the further scheduling of the base station. Therefore, acontention-free random access process just comprises 2 steps: the stepone is to transmit the preamble sequence, and the step 2 is to transmitthe random access response. Wherein:

The random access process in the LTE is applicable to the followingscenarios:

1. initial access under RRC_IDLE;

2. reestablishment of RRC connection;

3. cell handover;

4. when the uplink is nonsynchronous, the downlink data arrives in anRRC connected state and requests a random access process;

5. when the uplink is nonsynchronous or no resource is allocated for ascheduling request in a PUCCH resource, the uplink data arrives in anRRC connected state and requests a random access process; and

6. positioning.

Wherein, in the LTE, the six scenarios use the same random access steps.In the existing 5G standard discussion, communication systems adopt abeamforming mode. However, when a UE detects that there is a beamfailure, that is, when the quality of a downlink beam does not fulfill acertain condition any more, how the UE recovers the beam failure andinforms a base station of new available downlink transmission beams orwhether there are new available downlink transmission beams become aproblem.

SUMMARY

To overcome the technical problems or at least partially solve thetechnical problems, the following technical solutions are particularlyprovided.

According to one aspect, an embodiment of the present disclosureprovides a method for transmitting an uplink signal, comprising stepsof: detecting, by a user equipment (UE), whether there is a beamfailure; determining at least one of whether there is a candidatedownlink transmission beam(s) and candidate downlink transmission beaminformation, if the UE detects that there is a beam failure; andtransmitting, by the UE and according to a result of determining, a beamfailure recovery request message to a base station, the beam failurerecovery request message being used for informing the base station of atleast one of whether there is a candidate downlink transmission beam(s)and candidate downlink transmission beam information.

According to another aspect, an embodiment of the present disclosurefurther provides a user equipment (UE), comprising: a transceiverconfigured to detect whether there is a beam failure; a firstdetermination module configured to determine at least one of whetherthere is a candidate downlink transmission beam(s) and candidatedownlink transmission beam information if the transceiver detects thatthere is a beam failure; and the transceiver configured to transmit,according to a result of determination of the controller, a beam failurerecovery request message to a base station, wherein the beam failurerecovery request message is used for informing the base station of atleast of whether there is a candidate downlink transmission beam(s) andcandidate downlink transmission beam information.

According to another aspect, an embodiment of the present disclosurefurther provides a method for transmitting a downlink signal, comprisingsteps of: detecting, by a base station, a beam failure recovery requestmessage; determining, by the base station and according to the detectedbeam failure recovery request message, at least one of whether there isa candidate downlink transmission beam(s) and candidate downlinktransmission beam information in a user equipment; and transmitting, bythe base station and according to a result of determining, a feedbackmessage corresponding to the beam failure recovery request message.

According to another aspect, an embodiment of the present disclosurefurther provides a base station, comprising: a transceiver configured todetect a beam failure recovery request message; a controller configuredto determine, according to the beam failure recovery request messagedetected by the transceiver, at least one of whether there is acandidate downlink transmission beam(s) and candidate downlinktransmission beam information in a user equipment; and the transceiverconfigured to transmit, by the base station and according to a result ofdetermination of the controller, a feedback message corresponding to thebeam failure recovery request message.

The present disclosure provides methods, a UE and a base station fortransmitting an uplink signal and a downlink signal. In the presentdisclosure, a UE detects whether there is a beam failure currently,determines at least one of whether there is a candidate downlinktransmission beam(s) and candidate downlink transmission beaminformation currently if it is detected that there is a beam failurecurrently, and transmits, according to a result of determining, a beamfailure recovery request message to a base station. And, the basestation detects the beam failure recovery request message, anddetermines, according to the detected beam failure recovery requestmessage, at least one of whether there is a candidate downlinktransmission beam(s) and candidate downlink transmission beaminformation currently in the UE, and transmits, according to a result ofdetermining, a feedback message corresponding to the beam failurerecovery request message, wherein the beam failure recovery requestmessage is used for informing the base station of at least one ofwhether there is a candidate downlink transmission beam(s) and candidatedownlink transmission beam information currently. In other words, in thepresent disclosure, upon detecting that there is a beam failure andthere is a new candidate beam currently, a UE transmits a result ofdetection to a base station, so that the base station can know thatthere is a beam failure currently in the UE and that there is acandidate downlink transmission beam(s) currently in the UE. Thus, upondetecting that there is a beam failure, the UE can inform the basestation of a new available downlink transmission beam or whether thereis a new available downlink transmission beam.

Additional aspects and advantages of the present disclosure will bepartially appreciated and become apparent from the description below, orwill be well learned from the practices of the present disclosure.

Before undertaking the DETAILED DESCRIPTION below, it may beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document: the terms “include” and “comprise,” aswell as derivatives thereof, mean inclusion without limitation; the term“or,” is inclusive, meaning and/or; the phrases “associated with” and“associated therewith,” as well as derivatives thereof, may mean toinclude, be included within, interconnect with, contain, be containedwithin, connect to or with, couple to or with, be communicable with,cooperate with, interleave, juxtapose, be proximate to, be bound to orwith, have, have a property of, or the like; and the term “controller”means any device, system or part thereof that controls at least oneoperation, such a device may be implemented in hardware, firmware orsoftware, or some combination of at least two of the same. It should benoted that the functionality associated with any particular controllermay be centralized or distributed, whether locally or remotely.

Moreover, various functions described below can be implemented orsupported by one or more computer programs, each of which is formed fromcomputer readable program code and embodied in a computer readablemedium. The terms “application” and “program” refer to one or morecomputer programs, software components, sets of instructions,procedures, functions, objects, classes, instances, related data, or aportion thereof adapted for implementation in a suitable computerreadable program code. The phrase “computer readable program code”includes any type of computer code, including source code, object code,and executable code. The phrase “computer readable medium” includes anytype of medium capable of being accessed by a computer, such as readonly memory (ROM), random access memory (RAM), a hard disk drive, acompact disc (CD), a digital video disc (DVD), or any other type ofmemory. A “non-transitory” computer readable medium excludes wired,wireless, optical, or other communication links that transporttransitory electrical or other signals. A non-transitory computerreadable medium includes media where data can be permanently stored andmedia where data can be stored and later overwritten, such as arewritable optical disc or an erasable memory device.

Definitions for certain words and phrases are provided throughout thispatent document. Those of ordinary skill in the art should understandthat in many, if not most instances, such definitions apply to prior, aswell as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIG. 1 illustrates a schematic flowchart of a conventionalcontention-based random access;

FIG. 2A illustrates a schematic flowchart of a method for transmittingan uplink signal according to an embodiment of the present disclosure;

FIG. 2B illustrates a schematic flowchart exemplarily showing the step203 of FIG. 2A;

FIG. 2C illustrates a schematic flowchart exemplarily showing the step203 of FIG. 2A;

FIG. 3 illustrates a schematic flowchart of a method for transmitting anuplink signal according to an embodiment of the present disclosure;

FIG. 4A illustrates a schematic flowchart of another method fortransmitting an uplink signal according to an embodiment of the presentdisclosure;

FIG. 4B illustrates a schematic flowchart exemplarily showing the step303 of FIG. 4A;

FIG. 5 illustrates a schematic diagram of binding a beam failurerecovery request resource and a downlink beam according to an embodimentof the present disclosure;

FIG. 6 illustrates a schematic diagram of binding a downlinktransmission beam and a beam failure recovery request preamble groupaccording to an embodiment of the present disclosure;

FIG. 7 illustrates a schematic diagram of selecting a time-domainposition of an available time-frequency resource for the beam failurerecovery request according to an embodiment of the present disclosure;

FIG. 8 illustrates a schematic diagram of selecting a frequency positionof an available time-frequency resource for the beam failure recoveryrequest according to an embodiment of the present disclosure;

FIG. 9 illustrates a schematic diagram of implicitly informing of no newcandidate downlink transmission beam according to an embodiment of thepresent disclosure;

FIG. 10 illustrates a schematic structure diagram of a channel fortransmitting a beam failure recovery request in a scheduling-free manneraccording to an embodiment of the present disclosure;

FIG. 11 illustrates a schematic structure diagram of a user equipmentaccording to an embodiment of the present disclosure; and

FIG. 12 illustrates a schematic structure diagram of a base stationaccording to an embodiment of the present disclosure.

DETAILED DESCRIPTION

FIGS. 1 through 12, discussed below, and the various embodiments used todescribe the principles of the present disclosure in this patentdocument are by way of illustration only and should not be construed inany way to limit the scope of the disclosure. Those skilled in the artwill understand that the principles of the present disclosure may beimplemented in any suitably arranged system or device.

Embodiments of the present disclosure will be described in detailhereinafter. The examples of these embodiments have been illustrated inthe accompanying drawings throughout which same or similar referencenumerals refer to same or similar elements or elements having same orsimilar functions. The embodiments described with reference to theaccompanying drawings are illustrative, merely used for explaining thepresent disclosure and should not be regarded as any limitationsthereto.

It should be understood by one person of ordinary skill in the art thatsingular forms “a”, “an”, “the”, and “said” may be intended to includeplural forms as well, unless otherwise stated. It should be furtherunderstood that terms “comprise/comprising” used in this specificationspecify the presence of the stated features, integers, steps,operations, elements and/or components, but not exclusive of thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or combinations thereof. It shouldbe understood that, when a component is referred to as being “connectedto” or “coupled to” another component, it can be directly connected orcoupled to other elements or provided with intervening elements therebetween. In addition, “connected to” or “coupled to” as used herein cancomprise wireless connection or coupling. As used herein, the term“and/or” comprises all or any of one or more associated listed items orcombinations thereof.

It should be understood by one person of ordinary skill in the art that,unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneperson of ordinary skill in the art to which the present disclosurebelongs. It should be further understood that terms, such as thosedefined in commonly used dictionaries, should be interpreted as having ameaning that is consistent with their meanings in the context of the artand will not be interpreted in an idealized or overly formal senseunless expressly so defined herein.

It should be understood by one person of ordinary skill in the art thatthe term “terminal” and “terminal equipment” as used herein compassesnot only devices with a wireless signal receiver having no emissioncapability but also devices with receiving and emitting hardware capableof carrying out bidirectional communication over a bidirectionalcommunication link. Such devices can comprise cellular or othercommunication devices with a single-line display or multi-line displayor without a multi-line display; Personal Communication Systems (PCSs)with combined functionalities of speech, data processing, facsimileand/or data communication; Personal Digital Assistants (PDAs), which mayinclude RF receivers, pagers, internet networks/intranet accesses, webbrowsers, notepads, calendars and/or Global Positioning System (GPS)receivers; and/or conventional laptop and/or palmtop computers or otherdevices having and/or including a RF receiver. The “terminal” and“terminal equipment” as used herein can be portable, transportable,mountable in transportations (air, sea and/or land transportations), orsuitable and/or configured to run locally and/or distributed in otherplaces in the earth and/or space for running. The “terminal” or“terminal equipment” as used herein may be a communication terminal, aninternet terminal, a music/video player terminal. For example, it can bea PDA, a Mobile Internet Device (MID) and/or a mobile phone with amusic/video playback function, or can be equipment such as a smart TVand a set-top box.

In a beamforming system, for the beam failure recovery, there are fouraspects: beam failure detection, new candidate beam identification, beamfailure recovery request transmission, and UE monitors gNB response forbeam failure recovery request. Wherein, when a user equipment (UE) needsto transmit a beam failure recovery request, it may inform a basestation of its beam failure request in a manner similar to the randomaccess. The UE may also explicitly or implicitly inform the base stationof information such as available candidate beams.

Wherein, for implicitly informing, the transmission way may be asfollows: binding downlink signals using different downlink transmissionbeams with beam failure recovery request resources, wherein it may bestipulated that the beam failure recovery request resources may beconsistent in time position of random access channel resources, butoccupy different frequency-domain positions. On the UE side, after abeam failure is detected, by detecting and measuring an downlink signal,a candidate downlink transmission beam may be obtained or it may beknown whether there is a candidate downlink transmission beam(s); andthen, by using a binding relationship, the UE selects, according to aresult of downlink measurement, a beam failure recovery request resourceto transmit a beam failure recovery request signal (which may be apreamble signal, a reference signal in a predetermined format, or acontrol/data signal in a predetermined format, etc.). According to thedetected beam failure recovery request signal and the bindingrelationship, the base station may infer the new candidate downlinktransmission beam implicitly informed by the user.

Wherein, the downlink signal of the downlink transmission beam may be aperiodic Channel State Information-Reference Signal (CSI-RS) or asynchronous signal block (SS Block).

Wherein, for explicitly informing, the transmission way may be asfollows: when a UE detects a beam failure, information about a newcandidate downlink transmission beam or whether there is a new candidatedownlink transmission beam is directly transmitted to a base station byuplink. Wherein, the transmission way of the UE may be scheduling-freetransmission by using a predetermined scheduling-free time-frequencyresource. Alternatively, the UE may transmit a beam failure recoverysignal (which may be a scheduling request) to acquire an uplink grant byan uplink control channel and then perform uplink transmission by usingthe scheduled time-frequency resource.

FIG. 2A is a schematic flowchart of a method for transmitting an uplinksignal according to an embodiment of the present disclosure.

Step 201: A UE detects whether there is a beam failure currently; step202: if the UE detects that there is a beam failure currently, the UEdetermines whether there is a candidate downlink transmission beam(s)and/or candidate downlink transmission beam information currently; and,step 203: the UE transmits, according to a result of determining, a beamfailure recovery request message to a base station. Wherein, the beamfailure recovery request message is used for informing the base stationof whether there is a candidate downlink transmission beam(s) and/orcandidate downlink transmission beam information currently.

Further, the step 201 may comprise: detecting, by the UE, whether thereceiving power of a beam failure detection reference signal is lessthan or equal to a predetermined value; and, determining, by the UE andaccording to a result of detection, whether there is a beam failurecurrently.

Further, the step 202 may comprise: if the UE detects that there is abeam failure currently, determining, by the UE and by using channelstate information-reference signal configured by the network for beammanagement and/or a SS-Block configured by the network, whether there isa candidate downlink transmission beam(s) and/or candidate downlinktransmission beam information currently.

Wherein, after the step 202, the method further comprises: determining,by the UE and according to a result of determining and a bindingrelationship, a time-frequency resource used for transmitting the beamfailure recovery request message and/or a signal resource used fortransmitting the beam failure recovery request message.

Wherein, the binding relationship is a binding relationship between thecandidate downlink transmission beam information and/or the informationof whether there is a candidate downlink transmission beam(s) currentlyand the time-frequency resource and/or signal resource used fortransmitting the beam failure recovery request message.

Further, the step 203 comprises: transmitting, by the UE and by usingthe determined time-frequency resource and/or signal resource used fortransmitting the beam failure recovery request message, the beam failurerecovery request message to the base station.

Further, the way of determining, by the UE and according to a result ofdetermining and a binding relationship, a time-frequency resource usedfor transmitting the beam failure recovery request message comprises:

A step of if there is one or more candidate downlink transmission beamscurrently and the information of one or more candidate downlinktransmission beam(s) correspond to one time-frequency resource used fortransmitting the beam failure recovery request message, thistime-frequency resource is determined as the time-frequency resourceused for transmitting the beam failure recovery request message, and

A step of if there is one or more candidate downlink transmission beamscurrently and the information of one or more new candidate downlinktransmission beam(s) correspond to multiple time-frequency resourcesused for transmitting the beam failure recovery request message, the UEselects in a predetermined way a time-frequency resource as thetime-frequency resource used for transmitting the beam failure recoveryrequest message.

Wherein, the predetermined way comprises at least one of the following:equiprobable selection and priority-based selection.

Further, the way of determining, by the UE and according to a result ofdetermining and a binding relationship, a signal resource used fortransmitting the beam failure recovery request message comprises step ofthat if there are multiple candidate downlink transmission beamscurrently and information of multiple candidate downlink transmissionbeams, and each of the multiple candidate downlink transmission beamscorresponds to a different set of signal resources for the beam failurerecovery message, the UE randomly selects, from the set of signalresources for the beam failure recovery request message corresponding toeach candidate downlink transmission beam, a signal resource as thesignal resource used for transmitting the beam failure recovery requestmessage, and a step of if there are multiple candidate downlinktransmission beams currently and information of multiple candidatedownlink transmission beams, and the multiple candidate downlinktransmission beams correspond to a same set of signal resources for thebeam failure recovery request message, the UE randomly selects, from theset of signal resources for the beam failure recovery request message, asignal resource as the signal resource used for transmitting the beamfailure recovery request message.

Wherein, the UE acquires the binding relationship and a beam failurerecovery request resource by using at least one of a downlink controlchannel, a downlink broadcast channel and a downlink shared channel.

Further, the step of determining, by the UE and according to a result ofdetermination and a binding relationship, a time-frequency resource usedfor transmitting the beam failure recovery request message and/or asignal resource used for transmitting the beam failure recovery requestmessage may comprise: if the UE determines that there is no candidatedownlink transmission beam currently, determining, by the UE andaccording to the acquired network configuration information, acorresponding time-frequency resource used for transmitting the beamfailure recovery request message and/or a corresponding signal resourceused for transmitting the beam failure recovery request message.

FIG. 2B is a schematic flowchart exemplarily showing the step 203 ofFIG. 2A.

Referring FIG. 2B, step 203 of FIG. 2A may comprises step 2031, whichincludes determining, by the UE and according to configurationinformation of the base station, a reference signal and a data load, andstep 2032, which includes transmitting, by the UE and according to theresult of determination, the beam failure recovery request message tothe base station in accordance with a particular structure.

Wherein, the particular structure comprises the reference signal and thedata load. The data load may include a payload.

For example, the step of determining, by the UE and according toconfiguration information of the base station, the reference signal andthe data load may comprise: determining, by the UE and according to theconfiguration information of the base station, the reference signal as areference signal specific to the UE and the data load as a first dataload; or, determining, by the UE and according to the configurationinformation of the base station, the reference signal as a referencesignal not specific to the UE and the data load as a second data load.

Wherein, the first data load comprises a candidate downlink transmissionbeam existence indicator and/or one or more candidate downlinktransmission beam index determined by the UE; the second data load atleast comprises a candidate downlink transmission beam existenceindicator and/or one or more candidate downlink transmission beam indexdetermined by the UE and an unique identifier of the UE; and, thecandidate downlink transmission beam existence indicator is used foridentifying whether there is a candidate downlink transmission beam(s)currently in the UE, and the one or more candidate downlink transmissionbeam index determined by the UE is used for identifying one or morecandidate downlink transmission beam determined by the UE. Wherein, theunique identifier of the UE may comprise at least one of the following:a Cell Radio Network Temporary Identifier (C-RNTI), a Serving-TemporaryMobile Subscriber Identity (S-TMSI), and a random number generated bythe UE itself.

Wherein, the UE acquires the configuration information of the basestation by any one of a downlink control channel, a downlink broadcastchannel and a downlink shared channel.

Further, the step 203 may further comprise a step of that the UEtransmits a beam failure recovery request message by a Physical UplinkControl Channel (PUCCH).

Wherein, the beam failure recovery request message comprises beamfailure state indication information and a candidate downlinktransmission beam existence indicator and/or one or more candidatedownlink transmission beam index determined by the UE.

FIG. 2C is a schematic flowchart exemplarily showing the step 203 ofFIG. 2A.

Referring to FIG. 2C, step 203 of FIG. 2A may comprise steps 2033, 2034,and 2035. In Step 2033, the UE transmits a scheduling request message tothe base station by a PUCCH. In step 2034, the UE receives uplink grantinformation transmitted by the base station. In step 2035, the UEtransmits a beam failure recovery request message to the base station bya Physical Uplink Shared Channel (PUSCH).

Wherein, the beam failure recovery request message comprises beamfailure state indication information and a candidate downlinktransmission beam existence indicator and/or one or more candidatedownlink transmission beam index determined by the UE.

FIG. 3 is a schematic flowchart of a method for transmitting an uplinksignal according to an embodiment of the present disclosure. In thedescription of FIG. 3, the parts that are the same as those in FIG. 2Aare omitted.

Step 204: monitoring, by the UE, within the determined control channelsearch space and by using a particular scrambling code, a feedbackmessage transmitted by the base station.

Wherein, the feedback message is a feedback message corresponding to thebeam failure recovery request message.

Wherein, the determined control channel search space comprises at leastone of the following: a reference control channel search spaceconfigured by the base station; a downlink control channel search spacebetween the UE and the base station for the previous time; and, aparticular control channel search space configured by the UE when the UEis in an accessed state, the particular control channel search spacebeing used for searching the feedback message.

Wherein, the particular scrambling code comprises at least one of thefollowing: a Beam Failure Recovery Radio Network Temporary Identity(BFR-RNTI), a Cell Radio Network Temporary Identifier (C-RNTI), aServing-Temporary Mobile Subscriber Identity (S-TMSI), and a particularrandom number.

The method further comprise a step of that if the UE fails to detect thefeedback message transmitted by the base station and the number oftransmissions of the beam failure recovery request message by the UE isnot greater than the maximum permissible number of transmissions of thebeam failure recovery request message, the UE gradually increases,according to a predetermined power prompt interval, a transmitting powerfor transmitting the beam failure recovery request message, andtransmits the beam failure recovery request message.

The method further comprise a step of that if the UE fails to detect thefeedback message transmitted by the base station and the number oftransmissions of the beam failure recovery request message by the UEreaches the maximum permissible number of transmissions of the beamfailure recovery request message, the UE may transmit a failure messageto a higher layer, the failure message being used for informing thehigher layer that the beam failure recovery request is failed.

The method further comprise a step of that if the UE fails to detect thefeedback message transmitted by the base station, the UE may directlytransmit a failure message to the higher layer.

Wherein, when there is no candidate downlink transmission beamcurrently, the UE performs the following operations: if there is nocandidate downlink transmission beam currently, the UE transmits arandom access request message to the base station to perform randomaccess; or, if there is no candidate downlink transmission beamcurrently, the UE transmits a cell reselection request message to thebase station to perform cell reselection.

This embodiment of the present disclosure provides a method fortransmitting an uplink signal. In this embodiment of the presentdisclosure, a UE detects whether there is a beam failure currently,determines whether there is a candidate downlink transmission beam(s)and/or candidate downlink transmission beam information currently if itis detected that there is a beam failure currently, and transmits,according to the result of determination, a beam failure recoveryrequest message to a base station; and, the base station detects thebeam failure recovery request message, and determines, according to thedetected beam failure recovery request message, whether there is acandidate downlink transmission beam(s) and/or candidate downlinktransmission beam information currently in the UE, and transmits,according to the result of determination, a feedback messagecorresponding to the beam failure recovery request message, wherein thebeam failure recovery request message is used for informing the basestation of whether there is a candidate downlink transmission beam(s)and/or candidate downlink transmission beam information currently. Inother words, in this embodiment of the present disclosure, upondetecting that there is a beam failure and there is a new candidate beamcurrently, a UE transmits the result of detection to a base station, sothat the base station may know that there is a beam failure currently inthe UE and that there is a candidate downlink transmission beam(s)currently in the UE. Thus, upon detecting that there is a beam failure,the UE may inform the base station of a new available downlinktransmission beam or whether there is a new available downlinktransmission beam.

FIG. 4A is a schematic flowchart of a method for transmitting a downlinksignal according to another embodiment of the present disclosure.

Step 301: A base station detects a beam failure recovery requestmessage; step 302: the base station determines, according to thedetected beam failure recovery request message, whether there is acandidate downlink transmission beam(s) and/or candidate downlinktransmission beam information currently in a UE; and, step 303: the basestation transmits, according to the result of determination, a feedbackmessage corresponding to the beam failure recovery request message.

FIG. 4B is a schematic flowchart exemplarily showing the step 303 ofFIG. 4A.

Referring to FIG. 4B, the step 303 of FIG. 4A may comprise the followingsteps 3031-3032.

Step 3031: Determining, by the base station and according to the resultof determination, a way of transmitting a feedback message; and, step3032: Transmitting, by the base station and according to the determinedway of transmitting a feedback message, a feedback message correspondingto the beam failure recovery request message.

Further, the step 303 of FIG. 4A may comprise any one of the following(A, B, C, D, E, F, G and H).

A: If the base station determines that there is no candidate downlinktransmission beam currently in the UE, the base station determinesmultiple available downlink transmission beams, and transmits a feedbackmessage by using the multiple available downlink transmission beams in apolling manner;

B: if the base station determines that there is no candidate downlinktransmission beam currently in the UE, the base station determinesmultiple available downlink transmission beams, randomly selects adownlink transmission beam from the multiple available downlinktransmission beams, and transmits the feedback message by this downlinktransmission beam;

C: if the base station determines that there is no candidate downlinktransmission beam currently in the UE, the base station determines afirst downlink transmission beam, and transmits the feedback message tothe UE by the first downlink transmission beam. The first downlinktransmission beam is a downlink transmission beam which is used by thebase station to transmit a feedback message to the UE for the previoustime;

D: if the base station determines that there is only one candidatedownlink transmission beam currently in the UE, the base stationtransmits the feedback message to the UE by this candidate downlinktransmission beam;

E: if the base station determines that there is multiple candidatedownlink transmission beams currently in the UE, the base stationtransmits the feedback message to the UE by the multiple candidatedownlink transmission beams in a polling manner;

F: if the base station determines that there are multiple candidatedownlink transmission beams currently in the UE, the base stationrandomly selects a downlink transmission beam from the multiplecandidate downlink transmission beams, and transmits the feedbackmessage to the UE by this downlink transmission beam;

G: if the base station determines that there are multiple candidatedownlink transmission beams currently in the UE, the base station mayrandomly select, from the multiple candidate downlink transmissionbeams, a downlink transmission beam having a decreased angular deviationfrom the first downlink transmission beam, and transmits the feedbackmessage to the UE by this downlink transmission beam; and

H: if the base station determines that there are multiple candidatedownlink transmission beams currently in the UE, the base stationselects a second downlink transmission beam from the multiple candidatedownlink transmission beams, and transmits the feedback message to theUE by the second downlink transmission beam.

Wherein, the second downlink transmission beam is a downlinktransmission beam having a maximum receiving signal power among themultiple candidate downlink transmission beams.

Further, if the base station detects the beam failure recovery requestmessage, and the base station correctly demodulates the reference signalbut not the data load, the base station configures an uplink grant andtransmits the uplink grant to the UE.

This embodiment of the present disclosure provides methods fortransmitting an uplink signal and a downlink signal. In this embodimentof the present disclosure, a UE detects whether there is a beam failurecurrently, determines whether there is a candidate downlink transmissionbeam(s) and/or candidate downlink transmission beam informationcurrently if it is detected that there is a beam failure currently, andtransmits, according to the result of determination, a beam failurerecovery request message to a base station; and, the base stationdetects the beam failure recovery request message, and determines,according to the detected beam failure recovery request message, whetherthere is a candidate downlink transmission beam(s) and/or candidatedownlink transmission beam information currently in the UE, andtransmits, according to the result of determination, a feedback messagecorresponding to the beam failure recovery request message, wherein thebeam failure recovery request message is used for informing the basestation of whether there is a candidate downlink transmission beam(s)and/or candidate downlink transmission beam information currently. Inother words, in this embodiment of the present disclosure, upondetecting that there is a beam failure and there is a new candidate beamcurrently, a UE transmits the result of detection to a base station, sothat the base station may know that there is a beam failure currently inthe UE and that there is a candidate downlink transmission beam(s)currently in the UE. Thus, upon detecting that there is a beam failure,the UE may inform the base station of a new available downlinktransmission beam or whether there is a new available downlinktransmission beam.

In this embodiment of the present disclosure, the candidate downlinktransmission beam may be technically interpreted as a new candidatedownlink transmission beam.

In an embodiment of the present disclosure, an uplink transmission wayfor implicitly informing by a binding relationship will be describedhere.

As shown in FIG. 5, a downlink signal is transmitted by multipledifferent downlink transmission beams, and the multiple differentdownlink transmission beams are bound with corresponding random accesschannel resources. In this embodiment of the present disclosure, it isproposed that the downlink transmission beams are also bound with beamfailure recovery request resources.

Wherein, the downlink signal may be a periodic CSI-RS or an SS block.When the downlink transmission beam is bound with a beam failurerecovery request resource, the downlink transmission beam may be adownlink transmission beam index (DL Tx beam ID), an SS block index or aChannel State Information Reference Signal Index (CSI-RS Index).

Wherein, as shown in FIG. 5, the beam failure recovery request resourcemay be a time-frequency resource for transmitting a beam failurerecovery signal, or a beam failure recovery signal resource (e.g., abeam failure recovery request preamble resource). When multiple downlinktransmission beams are bound with a same time-frequency resource fortransmitting the beam failure recovery signal, beam failure recoveryrequest preambles may be divided into groups, and the different downlinktransmission beams are distinguished by different groups. As shown inFIG. 6, when downlink transmission beams 1 and 2 are bound with a sametime-frequency resource for the beam failure recovery request, in orderto distinguish the two downlink transmission beams, N (e.g., N=64)available beam failure recovery request preambles are divided into twogroups. Then, the downlink transmission beam 1 is bound with the beamfailure recovery request preamble group 0, and the downlink transmissionbeam 2 is bound with the beam failure recovery request preamble group 1.When the base station detects that the beam failure recovery requestpreamble is from the group 0, the base station may infer that the newcandidate downlink transmission beam implicitly informed by the UE isthe downlink transmission beam 1.

Particularly, when the beam failure recovery request resource is atime-frequency resource for the beam failure recovery request, thetime-domain position of the beam failure recovery request resource maybe the same as that of the corresponding random access channel resource.The corresponding random access channel resource refers to a randomaccess channel resource bound with the same downlink transmission beam.As shown in FIG. 6, the time-domain position of the beam failurerecovery request resource corresponding to the downlink transmissionbeam 1 is the same as that of the random access channel resourcecorresponding to the downlink transmission beam 1, but thefrequency-domain position of the beam failure recovery request resourceis different from that of the random access channel resource.

Accordingly, the flow of determining, by the UE, a beam failure recoveryrequest resource may be as follows.

Step 1: The UE detects, by using a beam failure detection referencesignal, that there is a beam failure.

Wherein, an example of detection way may be as follows: if the receivingpower of the detected beam failure detection reference signal is lessthan or equal to a predetermined limit value, the UE decides that thereis a beam failure.

Step 2: The UE determines, by using a beam identification referencesignal, a possible new candidate beam or whether there is a newcandidate downlink transmission beam. The way may be described as below.

a. Measurement is performed by measuring the CSI-RS configured by thenetwork, and the UE acquires, according to the result of measurement, acandidate downlink transmission beam or information about whether thereis a new candidate downlink transmission beam. Wherein, the newcandidate downlink transmission beam is characterized in that: when thereceiving signal power is greater than or equal to a predetermined limitvalue, specifically, if there is a downlink transmission beam having acorresponding receiving signal power at the UE greater than or equal tothe predetermined limit value, the UE indicates that there is a newcandidate downlink transmission beam; and, if the correspondingreceiving signal power of all the downlink transmission beams at the UEis less than the predetermined limit value, the UE indicates that thereis no new candidate downlink transmission beam.

b. Measurement is performed by measuring an SS-Block configured by thenetwork, and the UE acquires, according to the result of measurement, acandidate downlink transmission beam or information about whether thereis a new candidate downlink transmission beam. Wherein, the newcandidate downlink transmission beam is characterized in that: when thereceiving signal power is greater than or equal to a predetermined limitvalue, specifically, if there is a downlink transmission beam having acorresponding receiving signal power at the UE greater than or equal tothe predetermined limit value, the UE indicates that there is a newcandidate downlink transmission beam; and, if the correspondingreceiving signal power of all the downlink transmission beams at the UEis less than the predetermined limit value, the UE indicates that thereis no new candidate downlink transmission beam.

c. Measurement is performed by measuring an SS-Block configured by thenetwork and a CSI-RS for beam management, and the UE acquires, accordingto the result of measurement, a candidate downlink transmission beam orinformation about whether there is a new candidate downlink transmissionbeam. Wherein, the new candidate downlink transmission beam ischaracterized in that: when the receiving signal power is greater thanor equal to a predetermined limit value, specifically, if there is adownlink transmission beam having a corresponding receiving signal powerat the UE greater than or equal to the predetermined limit value, the UEindicates that there is a new candidate downlink transmission beam; and,if the corresponding receiving signal power of all the downlinktransmission beams at the UE is less than the predetermined limit value,the UE indicates that there is no new candidate downlink transmissionbeam.

Step 3: The UE transmits a beam failure recovery request.

Wherein, according to whether there is new candidate downlinktransmission beam information, the determined new candidate downlinktransmission beam and the binding relationship between candidatedownlink transmission beams and beam failure recovery request resources(including time-frequency resources and preamble resources), the UEdetermines a time-frequency resource for transmitting the beam failurerecovery request and a signal resource for the beam failure recoveryrequest, for example, a beam failure recovery request preamble. Wherein,when there is a candidate downlink transmission beam(s) in the UE, ifthe UE may determine an unique beam failure recovery requesttime-frequency resource (for example, an unique new candidate downlinktransmission beam is determined and this downlink transmission beam isbound with an unique beam failure recovery request time-frequencyresource, or multiple new candidate downlink transmission beams aredetermined and the multiple downlink transmission beams are bound with asame and unique beam failure recovery request time-frequency resource),this beam failure recovery request time-frequency resource is determinedas a time-frequency resource for transmitting the beam failure recoveryrequest signal.

If the UE detects that there are multiple candidate downlinktransmission beams (i.e., corresponding to multiple beam failurerecovery request time-frequency resources) or a candidate downlinktransmission beam corresponds to multiple beam failure recovery requesttime-frequency resources, the UE may perform the following operations:

1. selecting, from the available beam failure recovery requesttime-frequency resources, a beam failure recovery request time-frequencyresource in an equiprobable manner to transmit the beam failure recoveryrequest signal; and

2. determining, from the available beam failure recovery requesttime-frequency resources, a beam failure recovery request time-frequencyresource according to a certain priority principle to transmit the beamfailure recovery request signal, wherein the certain priority principlemay be as follows:

(a) An order of time unit positions of beam failure recovery requesttime-frequency resources. For example, a beam failure recovery requesttime-frequency resource at a former time unit position has a higherpriority, while a beam failure recovery request time-frequency resourceat a later time unit position has a lower priority. As shown in FIG. 7,if the available beam failure recovery request time-frequency resourcesare ordered in 0 to 6 time units, the beam failure recovery requesttime-frequency resource 0 has the highest priority, and ispreferentially selected by the UE. However, if the UE is unable toperform transmission on the beam failure recovery request time-frequencyresource 0 (for example, due to a processing delay, the signal may notbe prepared well on the beam failure recovery request time-frequencyresource 0), the UE will postpone to a beam failure recovery requesttime-frequency resource having the highest priority and capable oftransmitting the signal.

(b) The order of time unit positions of beam failure recovery requesttime-frequency resources is used as priority, and a frequency positionof a beam failure recovery request time-frequency resource is randomlyselected from the frequency unit positions of multiple beam failurerecovery request time-frequency resources at the selected time unitposition in an equiprobable manner. As shown in FIG. 8, after the timeposition 3 of the beam failure recovery request time-frequency resourceis selected, a frequency position of a beam failure recovery requesttime-frequency resource is randomly selected from frequency positions 0to 3 in an equiprobable manner.

In this embodiment of the present disclosure, if the UE acquires,according to the binding relationship, a set of multiple available beamfailure recovery request preambles, the UE randomly selects a beamfailure recovery request preamble from this set in an equiprobablemanner. However, if the multiple new candidate downlink transmissionbeams obtained by the UE are bound with a same time-frequency resource,then:

1. If the multiple new candidate downlink transmission beams are boundwith different sets of beam failure recovery request preambles, as shownin FIG. 6, the UE randomly selects, according to the set of beam failurerecovery request preambles bound with the selected new candidatedownlink transmission beam, a beam failure recovery request preamblefrom this set in an equiprobable manner; and

2. if the multiple new candidate downlink transmission beams are boundwith a same set of beam failure recovery request preambles, the UErandomly selects a beam failure recovery request preamble from theavailable set and then transmits this beam failure recovery requestpreamble; and if the base station may successfully detect this beamfailure recovery request preamble, the base station may determine thatthere are multiple corresponding new candidate downlink transmissionbeams in the UE transmitting this beam failure recovery requestpreamble.

Wherein, the way of acquiring the configured beam failure recoveryrequest resources and the binding relationship between the downlinktransmission beams and the beam failure recovery request resources maybe realized by the UE by using a downlink control channel, a downlinkbroadcast channel or a downlink shared channel.

In this embodiment of the present disclosure, the determined newcandidate downlink transmission beam may be:

1. a downlink transmission beam with the highest receiving signal power,or a downlink transmission beam randomly selected from multiple downlinktransmission beams with the highest receiving signal power;

2. multiple downlink transmission beams with the highest receivingsignal power;

3. a downlink transmission beam with a receiving signal power greaterthan a predetermined threshold, or a downlink transmission beam randomlyselected from multiple downlink transmission beams with a receivingsignal power greater than the predetermined threshold; and

4. multiple downlink transmission beams with a receiving signal powergreater than the predetermined threshold.

In this embodiment of the present disclosure, when the UE fails todetermine a new candidate downlink transmission beam, a beam failurerecovery request resource for indicating that the UE determines a beamfailure but fails to bind any downlink transmission beam is obtainedthrough the obtained network configuration. Here, the beam failurerecovery request resource may be:

1. a beam failure recovery request time-frequency resource, wherein, asshown in FIG. 9, when the base station detects any beam failure recoveryrequest signal on this beam failure recovery request time-frequencyresource, the base station decides that there is a beam failure but nodetermined new candidate downlink transmission beam in the UEtransmitting this signal; and

2. a set of beam failure recovery request signal resources (e.g.,preamble resources), wherein, if this set exists, this set contains atleast one available beam failure recovery request signal resource; whenthe base station detects, on any beam failure recovery requesttime-frequency resource, a beam failure recovery request signalbelonging to this set of beam failure recovery request signal resources,the base station detects that there is a beam failure but no determinednew candidate downlink transmission beam in the UE transmitting thissignal. Step 4: The UE tries to receive a beam failure recovery requestfeedback from the base station. The UE will monitor, within thedetermined control channel search space and by using a particularscrambling code, the beam failure recovery request feedback possiblytransmitted by the base station.

Wherein, the determined control channel search space may be: a downlinkcontrol channel search space between the UE and the base station for thelast time; a reference control channel search space configured by thebase station; or, a particular control channel search space configuredby the UE when the UE is in an accessed state, the particular controlchannel search space being used for searching the beam failure recoveryrequest feedback. The particular scrambling code may be: a BFR-RNTI,which is calculated in a manner similar to a random access radio networktemporary identifier and is related to the position of thetime-frequency resource for transmitting the beam failure recoveryrequest of the UE; a C-RNTI, when the base station may determine theidentity of the UE transmitting the beam failure recovery requestsignal, wherein:

when the base station successfully detects a beam failure recoveryrequest signal and determines, from the detected beam failure recoveryrequest signal, that there are N new candidate downlink transmissionbeams in the UE transmitting this signal, then: when N=0, the basestation may perform the following operations:

a) using multiple possible downlink transmission beams to transmit abeam failure recovery request feedback signal in a polling manner;

b) selecting a downlink transmission beam to transmit a beam failurerecovery request feedback signal, where the principle is as follows:

i. randomly selecting one downlink transmission beam from multipleavailable downlink transmission beams in an equiprobable manner; and

ii. preferentially selecting a downlink transmission beam having a smallangular deviation from the downlink transmission beam used by the UE forthe last time; and

c) using the downlink transmission beam used by the UE for the last timeto transmit a beam failure recovery request feedback signal;

when N=1, the base station selects this downlink transmission beam totransmit a beam failure recovery request feedback signal; and

when N>1, the base station may adopt the following ways:

a) using the N downlink transmission beams informed by the UE totransmit a beam failure recovery request feedback signal in a pollingmanner; and

b) selecting a downlink transmission beam from the informed N candidatedownlink transmission beams to transmit a beam failure recovery requestfeedback signal (the N may be less than the number of downlinktransmission beams available for the base station; for example, thereare total 16 available downlink beams for the base station, but the userinforms N=4 candidate downlink transmission beams), where the principleis as follows:

i. randomly selecting one downlink transmission beam from the N downlinktransmission beams in an equiprobable manner; and

ii. preferentially selecting, from the N candidate beams, a downlinktransmission beam having a small angular deviation from the downlinktransmission beam used by the UE for the last time.

In this embodiment of the present disclosure, the beam failure recoveryrequest response signal may comprise a new timing advance, an uplinkgrant or more.

In this embodiment of the present disclosure, when the UE fails toreceive a correct beam failure recovery request response signal withinthe determined control channel search space, the UE may perform thefollowing operations.

1. The UE returns to the step 3 where a beam failure recovery requestsignal is transmitted, wherein the value of a counter for the beamfailure recovery request signal will be increased by 1, and the value ofthe counter for the beam failure recovery request signal should be lessthan or equal to the maximum permissible number of transmissions of thebeam failure recovery request signal. Meanwhile, when the beam failurerecovery request signal is retransmitted once, the transmitting power isincreased once at a given power prompt interval ΔP. When the number oftransmissions of the beam failure recovery request exceeds the maximumpermissible number of transmissions and the beam failure is still notrecovered, the UE reports a higher layer that the beam failure recoveryrequest is failed. For example, if the power of the beam failurerecovery request signal transmitted this time is P, but the UE fails todetect a correct beam failure recovery request response signal and thenumber of transmissions is within the maximum permissible number oftransmissions of the beam failure recovery request signal, the usertransmits a beam failure recovery request signal next time by usingP+ΔP.

2. The UE directly reports the higher layer that the beam failurerecovery request is failed.

In an embodiment of the present disclosure, the uplink transmission wayfor explicitly informing in a scheduling-free manner provided by thepresent disclosure will be described here. A UE transmits a beam failurerecovery request to a base station in a scheduling-free manner.

As shown in FIG. 10, the UE transmits a beam failure recovery request byusing a channel structure combining a reference signal and a data load,wherein, in the channel structure combining the reference signal and thedata load, the position of the reference signal and the position of thedata load may be exchanged, that is, cyclic prefix+data load+cyclicprefix+reference signal+guard interval; the reference signal may be aDemodulation Reference Signal (DMRS) or a preamble sequence; and theboth may be used for channel estimation, wherein:

1. when the reference signal is allocated to the UE by the base station,that is, the reference signal is a reference signal specific to the UE,the data load of the UE contains:

a) a new candidate downlink transmission beam existence indicator, forexample, 1-bit new candidate downlink transmission beam existenceindicator, wherein “1” indicates that there is a new candidate downlinktransmission beam in the UE transmitting the beam failure recoveryrequest, and “0” indicates that there is no new candidate downlinktransmission beam in the UE transmitting the beam failure recoveryrequest;

b) when the UE determines that there is a new candidate downlinktransmission beam, one or more specific downlink transmission beamindexes may be put into the data load and then informed to the basestation.

Wherein, the downlink transmission beam index may be a beamidentification reference signal index. For example, when the beamidentification reference signal is a synchronous signal block, thedownlink transmission beam index is a synchronous signal block index;and, when the beam identification reference signal is a channel stateinformation-reference signal configured by the base station for beammanagement, the downlink transmission beam index is a channel stateinformation-reference signal index.

2. When the reference signal is a reference signal randomly selected, bythe UE, from a group of reference signals configured by the basestation, the data load of the UE contains:

a) an unique identifier of the UE, for example, a C-RNTI of the UE, or aServing-Temporary Mobile Subscriber Identity (S-TMSI), or a randomnumber generated by the UE;

b) a new candidate downlink transmission beam existence indicator, forexample, 1-bit new candidate downlink transmission beam existenceindicator, wherein “1” indicates that there is a new candidate downlinktransmission beam in the UE transmitting the beam failure recoveryrequest, and “0” indicates that there is no new candidate downlinktransmission beam in the UE transmitting the beam failure recoveryrequest.

In this embodiment of the present disclosure, when the UE determinesthat there is a new candidate downlink transmission beam, one or morespecific downlink transmission beam indexes may be put into the dataload and then informed to the base station.

Wherein, the downlink transmission beam index may be a beamidentification reference signal index. For example, when the beamidentification reference signal is a synchronous signal block, thedownlink transmission beam index is a synchronous signal block index;and, when the beam identification reference signal is a channel stateinformation reference signal configured by the base station for beammanagement, the downlink transmission beam index is a channel stateinformation reference signal index.

Accordingly, the flow of determining, by the UE, a beam failure recoveryrequest resource is as follows.

Step 1: The UE detects, by using a beam failure detection referencesignal, that there is a beam failure. Wherein, the specific detectionway may be as follows: if the receiving power of the detected beamfailure detection reference signal is less than or equal to apredetermined limit value, the UE determines that there is a beamfailure.

Step 2: The UE determines, by using a beam identification referencesignal, a possible new candidate beam or whether there is a newcandidate downlink transmission beam. The way may be as follows:

1. measurement is performed by measuring the CSI-RS configured by thenetwork for beam management, and the UE acquires, according to theresult of measurement, a candidate downlink transmission beam orinformation about whether there is a new candidate downlink transmissionbeam, wherein the new candidate downlink transmission beam ischaracterized in that: when the receiving signal power is greater thanor equal to a predetermined limit value, specifically, if there is adownlink transmission beam having a corresponding receiving signal powerat the UE greater than or equal to the predetermined limit value, the UEindicates that there is a new candidate downlink transmission beam; and,if the corresponding receiving signal power of all the downlinktransmission beams at the UE is less than the predetermined limit value,the UE indicates that there is no new candidate downlink transmissionbeam;

2. measurement is performed by measuring an SS-Block configured by thenetwork, and the UE acquires, according to the result of measurement, acandidate downlink transmission beam or information about whether thereis a new candidate downlink transmission beam, wherein the new candidatedownlink transmission beam is characterized in that: when the receivingsignal power is greater than or equal to a predetermined limit value,specifically, if there is a downlink transmission beam having acorresponding receiving signal power at the UE greater than or equal tothe predetermined limit value, the UE indicates that there is a newcandidate downlink transmission beam; and, if the correspondingreceiving signal power of all the downlink transmission beams at the UEis less than the predetermined limit value, the UE indicates that thereis no new candidate downlink transmission beam; and

3. measurement is performed by measuring an SS-Block configured by thenetwork and a CSI-RS for beam management, and the UE acquires, accordingto the result of measurement, a candidate downlink transmission beam orinformation about whether there is a new candidate downlink transmissionbeam, wherein the new candidate downlink transmission beam ischaracterized in that, when the receiving signal power is greater thanor equal to a predetermined limit value, specifically, if there is adownlink transmission beam having a corresponding receiving signal powerat the UE greater than or equal to the predetermined limit value, the UEindicates that there is a new candidate downlink transmission beam; and,if the corresponding receiving signal power of all the downlinktransmission beams at the UE is less than the predetermined limit value,the UE indicates that there is no new candidate downlink transmissionbeam.

Step 3: The UE transmits a beam failure recovery request.

In this embodiment of the present disclosure, the UE determines,according to the configuration information of the base station, theposition of a time-frequency resource for transmitting the beam failurerecovery request, power information and Modulation and Coding Scheme(MCS) configuration, and determines the constitution of the referencesignal and data load in the beam failure recovery request signal.

In this embodiment of the present disclosure, if the base stationconfigures multiple available time-frequency resources, the UE randomlyselects, from the multiple configured available time-frequency resourcesand in an equiprobable manner, a time-frequency resource to transmit thebeam failure recovery request in a scheduling-free manner.

In this embodiment of the present disclosure, when the reference signalis a reference signal specific to the UE, the data load at leastcomprises a new candidate downlink transmission beam existenceindicator, and/or one or more new candidate downlink transmission beamindex determined by the UE. Particularly:

1. The order of reporting is arranged according to the receiving powerof the detected downlink transmission beams.

For example, if the base station transmits five downlink transmissionbeams having an index from 0 to 4, the UE detects downlink beams 1 to 3,and the receiving power (e.g., Reference Signal Receiving Power (RSRP))of the three beams is #2>#3>#1, new candidate downlink transmission beamindexes are reported in an order of 2, 3 and 1.

2. Only one downlink transmission beam index having the highestreceiving power is reported.

For example, if the base station transmits five downlink transmissionbeams having an index from 0 to 4, the UE detects downlink transmissionbeams corresponding to #1 to #3, and the receiving power (e.g., RSRP) ofthe three beams is #2>#3>#1, only the downlink transmission beam index 2is reported when reporting the new candidate downlink transmission beamindexes; and, if there are multiple downlink transmission beams havingthe highest receiving power, one downlink transmission beam is selectedfrom the multiple downlink transmission beams in an equiprobable mannerfor reporting. For example, if beams #2 and #3 are identical and highestin receiving power, the UE randomly selects one from 2 and 3 forreporting.

In this embodiment of the present disclosure, when the reference signalis a signal not specific to the UE, for example, a reference signalrandomly selected from a set of available reference signals by the UE,the data load should also at least comprise a unique identifier of theUE, for example, C-RNTI of the UE, S-TMSI or a random number generatedby the UE itself.

In this embodiment of the present disclosure, the configurationinformation of the base station is informed to the UE by the basestation through a downlink broadcast channel, a downlink control channelor a downlink shared channel.

Step 4: The UE tries to receive a beam failure recovery request feedbackfrom the base station.

In this embodiment of the present disclosure, the UE will monitor,within the determined control channel search space and by using aparticular scrambling code, the beam failure recovery request feedbackpossibly transmitted by the base station. Wherein, the determinedcontrol channel search space may be:

1. a downlink control channel search space between the UE and the basestation for the last time;

2. a reference control channel search space configured by the basestation; and

3. a particular control channel search space for searching the beamfailure recovery request feedback configured by the UE when the UE is inan accessed state.

Wherein, the particular scrambling code may be:

1. a BFR-RNTI, which is calculated in a manner similar to a randomaccess radio network temporary identifier and is related to the positionof the time-frequency resource for transmitting the beam failurerecovery request of the UE;

2. a C-RNTI, which is a C-RNTI reported in the data load by the UE;

3. an S-TMSI, which is an S-TMSI reported in the data load by the UE;and

4. a particular random number, which is a random number reported in thedata load by the UE.

For this embodiment of the present disclosure, when the base stationsuccessfully detects the beam failure recovery request signal (i.e.,correctly detects the reference signal and correctly demodulates thedata load) and determines, from the detected beam failure recoveryrequest signal, that there are N new candidate downlink transmissionbeams in the UE transmitting this signal, then:

1. when N=0, the base station may perform the following operations:

a) using multiple possible downlink transmission beams to transmit thebeam failure recovery request feedback signal in a polling manner;

b) selecting a downlink transmission beam to transmit the beam failurerecovery request feedback signal, where the principle is as follows:

i. randomly selecting one downlink transmission beam from multipledownlink transmission beams in an equiprobable manner; and

ii. preferentially selecting a downlink transmission beam having a smallangular deviation from the downlink transmission beam used by the UE forthe last time; and

c) using the downlink transmission beam used by the UE for the last timeto transmit the beam failure recovery request feedback signal;

2. when N=1, the base station selects this downlink transmission beam totransmit a beam failure recovery request feedback signal; and

3. when N>1, the base station may perform the following operations:

a) using the N downlink transmission beams informed by the UE totransmit the beam failure recovery request feedback signal in a pollingmanner;

b) selecting a downlink transmission beam from the N informed candidatedownlink transmission beams to transmit the beam failure recoveryrequest feedback signal (the N may be less than the number of downlinktransmission beams available for the base station; for example, thereare total 16 available downlink beams for the base station, but the userinforms N=4 candidate downlink transmission beams), where the principleis as follows:

i. randomly selecting one downlink transmission beam from the N downlinktransmission beams in an equiprobable manner; and

ii. preferentially selecting, from the N candidate downlink beams, adownlink transmission beam having a small angular deviation from thedownlink transmission beam used by the UE for the last time; and

iii. selecting, from the downlink transmission beams, a downlinktransmission beam having the highest receiving signal power, forexample, the top one among the N downlink transmission beams, whereinthe beam failure recovery request response signal may comprise a newtiming advance, an uplink grant or more.

In this embodiment of the present disclosure, when the base stationsuccessfully detects the reference signal in the beam failure recoveryrequest signal but fails to correctly demodulates the data load, it isindicated that the base station knows that there is a beam failure inthe UE transmitting this request signal, and an uplink grant isconfigured in the beam failure recovery request response signal so thatthe UE may report whether there is a new candidate downlink transmissionbeam(s) or one or more new candidate downlink transmission beam index.

In this embodiment of the present disclosure, when the UE fails toreceive a correct beam failure recovery request response signal withinthe determined control channel search space, the UE may perform thefollowing operations.

1. The UE returns to the step 3 where a beam failure recovery requestsignal is transmitted.

Wherein, the value of a counter for the beam failure recovery requestsignal will be increased by 1, and the value of the counter for the beamfailure recovery request signal should be less than or equal to themaximum permissible number of transmissions of the beam failure recoveryrequest signal. When the number of transmissions of the beam failurerecovery request signal exceeds the maximum permissible number oftransmissions and the beam failure is not yet recovered, the UE reportsa higher layer that the beam failure recovery request is failed.

2. The UE directly reports the higher layer that the beam failurerecovery request is failed.

In an embodiment of the present disclosure, the uplink transmission wayfor explicitly informing by the obtained uplink channel signal providedby the present disclosure will be described here.

In this embodiment of the present disclosure, the UE transmits a beamfailure recovery request signal through an uplink channel:

1. A beam failure state, a new candidate downlink transmission beamexistence state and (one or more) new candidate downlink transmissionbeam indexes are directly reported by a PUCCH, for example:

a) 1-bit beam failure state, wherein “1” represents a beam failure and“0” represents no beam failure;

b) 1-bit new candidate downlink transmission beam existence state,wherein “1” indicates that there is a new candidate downlinktransmission beam and “0” indicates that there is no new candidatedownlink transmission beam;

c) M N-bit new candidate downlink transmission beam indexes, wherein, ifthe base station has four downlink transmission beams and three of thedownlink transmission beams are candidate downlink transmission beamsdetermined by the UE, three 2-bit new candidate downlink transmissionbeams are used.

In this embodiment of the present disclosure, after a scheduling requestis transmitted by a PUCCH to acquire an uplink grant, the UE reports, ina PUSCH, a beam failure state, a new candidate downlink transmissionbeam existence state and (one or more) new candidate downlinktransmission beam indexes. The specific process is as described aboveand will not be repeated here.

Accordingly, the flow of determining, by the UE, a beam failure recoveryrequest resource is as follows.

Step 1: The UE detects, by using a beam failure detection referencesignal, that there is a beam failure.

Specifically, the detection way may be as follows: if the receivingpower of the detected beam failure detection reference signal is lessthan or equal to a predetermined limit value, the UE decides that thereis a beam failure.

Step 2: The UE determines, by using a beam identification referencesignal, a possible new candidate beam or whether there is a newcandidate downlink transmission beam.

Wherein, the way of determining a possible new candidate beam or whetherthere is a new candidate downlink transmission beam is similar to thedescription in the forgoing embodiments and will not be repeated here.

Step 3: The UE transmits a beam failure recovery request.

In this embodiment of the present disclosure, the UE determines,according to the configuration information of the base station, theposition of a PUCCH time-frequency resource for transmitting the beamfailure recovery request. Data of the beam failure state, the newcandidate downlink transmission beam existence state and the (one ormore) new candidate downlink transmission beam indexes are determined inadvance.

In this embodiment of the present disclosure, the configurationinformation of the base station is informed to the UE by the basestation through a downlink broadcast channel, a downlink control channelor a downlink shared channel.

Step 4: The UE tries to receive a beam failure recovery request feedbackfrom the base station. The UE will monitor, within the determinedcontrol channel search space and by using a particular scrambling code,the beam failure recovery request feedback possibly transmitted by thebase station.

Wherein, the determined control channel search space and the particularscrambling code may refer to the description of the foregoingembodiments and will not be repeated here.

In this embodiment of the present disclosure, when the base stationsuccessfully detects a beam failure recovery request signal anddetermines, from the detected beam failure recovery request signal, thatthere are N new candidate downlink transmission beams in the UEtransmitting this signal, wherein:

1. when N=0, the base station may perform the following operations:

a) using multiple possible downlink transmission beams to transmit thebeam failure recovery request feedback signal in a polling manner;

b) selecting a downlink transmission beam to transmit the beam failurerecovery request feedback signal, where the principle is as follows:

i. randomly selecting one downlink transmission beam from multipleavailable downlink transmission beams in an equiprobable manner; and

ii. preferentially selecting a downlink transmission beam having a smallangular deviation from the downlink transmission beam used by the UE forthe last time; and

c) using the downlink transmission beam used by the UE for the last timeto transmit the beam failure recovery request feedback signal;

2. when N=1, the base station selects this downlink transmission beam totransmit the beam failure recovery request feedback signal; and

3. when N>1, the base station may perform the following operations:

a) using the N downlink transmission beams informed by the UE totransmit the beam failure recovery request feedback signal in a pollingmanner;

b) selecting a downlink transmission beam from the N informed candidatedownlink transmission beams to transmit the beam failure recoveryrequest feedback signal (the N may be less than the number of downlinktransmission beams available for the base station; for example, thereare total 16 available downlink beams for the base station, but the UEinforms N=4 candidate downlink transmission beams), where the principleis as follows:

i. randomly selecting one downlink transmission beam from the N downlinktransmission beams in an equiprobable manner;

ii. preferentially selecting, from the N candidate downlink beams, adownlink transmission beam having a small angular deviation from thedownlink transmission beam used by the UE for the last time; and

iii. selecting, from the downlink transmission beams, a downlinktransmission beam having the highest receiving signal power, forexample, the top one among the N downlink transmission beams.

In this embodiment of the present disclosure, the beam failure recoveryrequest response signal may comprise a new timing advance, an uplinkgrant or more.

In this embodiment of the present disclosure, when the UE fails toreceive a correct beam failure recovery request response signal withinthe determined control channel search space, the UE may perform thefollowing operations.

1. The UE returns to the step 3 where a beam failure recovery requestsignal is transmitted, wherein the value of a counter for the beamfailure recovery request signal will be increased by 1, and the value ofthe counter for the beam failure recovery request signal should be lessthan or equal to the maximum permissible number of transmissions of thebeam failure recovery request signal. When the number of transmissionsof the beam failure recovery request exceeds the maximum permissiblenumber of transmissions and the beam failure is not yet recovered, theUE reports a higher layer that the beam failure recovery request isfailed.

2. The UE directly reports the higher layer that the beam failurerecovery request is failed.

In an embodiment of the present disclosure, the initiation of randomaccess or cell reselection when the UE fails to detect any candidatedownlink transmission beam will be described here.

In this embodiment, the processing steps of the UE are as follows.

Step 1: The UE detects, by using a beam failure detection referencesignal, that there is a beam failure.

Specifically, the detection way may be as follows: if the receivingpower of the detected beam failure detection reference signal is lessthan or equal to a predetermined limit value, the UE decides that thereis a beam failure.

Step 2: The UE determines, by using a beam identification referencesignal, a possible new candidate beam or whether there is a newcandidate downlink transmission beam.

In this embodiment of the present disclosure, when the UE detects thereis an available new candidate downlink transmission beam, the processingmethod refers to the processing methods in the forgoing embodiments andwill not be repeated here.

Particularly, when the UE detects that there is no available newcandidate downlink transmission beam, the UE may stop the beam failurerecovery and initiate a random access process; or may stop the beamfailure recovery and initiate cell reselection.

An embodiment of the present disclosure provides a UE, as shown in FIG.11, comprising a transceiver 1010, a controller 1020, wherein:

the transceiver 1010 is configured to detect whether there is a beamfailure currently;

the controller 1020 is configured to determine whether there is acandidate downlink transmission beam(s) and/or candidate downlinktransmission beam information when the transceiver 1010 detects thatthere is a beam failure currently; and

the transceiver 1010 is configured to transmit, according to the resultof determination of the controller 1020, a beam failure recovery requestmessage to a base station.

Wherein, the beam failure recovery request message is used for informingthe base station of whether there is a candidate downlink transmissionbeam(s) and/or candidate downlink transmission beam informationcurrently.

This embodiment of the present disclosure provides a UE. In thisembodiment of the present disclosure, a UE detects whether there is abeam failure currently, determines whether there is a candidate downlinktransmission beam(s) and/or candidate downlink transmission beaminformation currently if it is detected that there is a beam failurecurrently, and transmits, according to the result of determination, abeam failure recovery request message to a base station; and, the basestation detects the beam failure recovery request message, anddetermines, according to the detected beam failure recovery requestmessage, whether there is a candidate downlink transmission beam(s)and/or candidate downlink transmission beam information currently in theUE, and transmits, according to the result of determination, a feedbackmessage corresponding to the beam failure recovery request message,wherein the beam failure recovery request message is used for informingthe base station of whether there is a candidate downlink transmissionbeam(s) and/or candidate downlink transmission beam informationcurrently. In other words, in this embodiment of the present disclosure,upon detecting that there is a beam failure and there is a new candidatebeam currently, a UE transmits the result of detection to a basestation, so that the base station may know that there is a beam failurecurrently in the UE and that there is a candidate downlink transmissionbeam(s) currently in the UE. Thus, upon detecting that there is a beamfailure, the UE may inform the base station of a new available downlinktransmission beam or whether there is a new available downlinktransmission beam.

The user equipment (UE) provided in this embodiment of the presentdisclosure may implement the method embodiments described above, and thespecific function implementations refer to the descriptions in themethod embodiments and will not be repeated here.

An embodiment of the present disclosure provides a base station, asshown in FIG. 12, comprising transceiver 1110, a controller 1120 and atransceiver 1110, wherein:

the transceiver 1110 is configured to detect a beam failure recoveryrequest message; the controller 1120 is configured to determine,according to the beam failure recovery request message detected by thetransceiver 1110, whether there is a candidate downlink transmissionbeam(s) and/or candidate downlink transmission beam informationcurrently in a UE; and

the transceiver 1110 is configured to transmit, by the base station andaccording to the result of determination of the controller 1120, afeedback message corresponding to the beam failure recovery requestmessage

This embodiment of the present disclosure provides a base station. Inthis embodiment of the present disclosure, a UE detects whether there isa beam failure currently, determines whether there is a candidatedownlink transmission beam(s) and/or candidate downlink transmissionbeam information currently if it is detected that there is a beamfailure currently, and transmits, according to the result ofdetermination, a beam failure recovery request message to a basestation; and, the base station detects the beam failure recovery requestmessage, and determines, according to the detected beam failure recoveryrequest message, whether there is a candidate downlink transmissionbeam(s) and/or candidate downlink transmission beam informationcurrently in the UE, and transmits, according to the result ofdetermination, a feedback message corresponding to the beam failurerecovery request message, wherein the beam failure recovery requestmessage is used for informing the base station of whether there is acandidate downlink transmission beam(s) and/or candidate downlinktransmission beam information currently. In other words, in thisembodiment of the present disclosure, upon detecting that there is abeam failure and there is a new candidate beam currently, a UE transmitsthe result of detection to a base station, so that the base station mayknow that there is a beam failure currently in the UE and that there isa candidate downlink transmission beam(s) currently in the UE. Thus,upon detecting that there is a beam failure, the UE may inform the basestation of a new available downlink transmission beam or whether thereis a new available downlink transmission beam.

The base station provided in this embodiment of the present disclosuremay implement the method embodiments described above, and the specificfunction implementations refer to the descriptions in the methodembodiments and will not be repeated here.

It should be understood by those skilled in the art that the presentdisclosure involves devices for carrying out one or more of operationsas described in the present disclosure. Those devices may be speciallydesigned and manufactured as intended, or may comprise well knowndevices in a general-purpose computer. Those devices have computerprograms stored therein, which are selectively activated orreconstructed. Such computer programs may be stored in device (such ascomputer) readable media or in any type of media suitable for storingelectronic instructions and respectively coupled to a bus, the computerreadable media include but are not limited to any type of disks(including floppy disks, hard disks, optical disks, CD-ROM and magnetooptical disks), ROM (Read-Only Memory), RAM (Random Access Memory),EPROM (Erasable Programmable Read-Only Memory), EEPROM (ElectricallyErasable Programmable Read-Only Memory), flash memories, magnetic cardsor optical line cards. In other words, the readable media comprise anymedia storing or transmitting information in a device (for example,computer) readable form.

It should be understood by those skilled in the art that computerprogram instructions may be used to realize each block in structurediagrams and/or block diagrams and/or flowcharts as well as acombination of blocks in the structure diagrams and/or block diagramsand/or flowcharts. It should be understood by those skilled in the artthat these computer program instructions may be provided to generalpurpose computers, special purpose computers or other processors ofprogrammable data processing means to be implemented, so that solutionsdesignated in a block or blocks of the structure diagrams and/or blockdiagrams and/or flow diagrams are executed by computers or otherprocessors of programmable data processing means.

It should be understood by those skilled in the art that the steps,measures and solutions in the operations, methods and flows alreadydiscussed in the present disclosure may be alternated, changed, combinedor deleted. Further, other steps, measures and solutions in theoperations, methods and flows already discussed in the presentdisclosure may also be alternated, changed, rearranged, decomposed,combined or deleted. Further, the steps, measures and solutions of theprior art in the operations, methods and operations disclosed in thepresent disclosure may also be alternated, changed, rearranged,decomposed, combined or deleted.

Although the present disclosure has been described with variousembodiments, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present disclosure encompasssuch changes and modifications as fall within the scope of the appendedclaims.

What is claimed is:
 1. A method performed by a terminal in a wirelesscommunication system, the method comprising: receiving, from a basestation, first information including information on at least onereference signal to be used for identifying one or more candidate beamsassociated with a beam failure recovery request and second informationon a search space associated with a beam failure recovery response;selecting a reference signal based on the first information;transmitting to the base station, a random access preamble for the beamfailure recovery request based on the selected reference signal;identifying the search space for monitoring a downlink control channelbased on the second information, the search space being used for thebeam failure recovery response; monitoring the downlink control channelbased on the identified search space, the downlink control channel beingidentified by a cell radio network temporary identifier (C-RNTI); andreceiving, from the base station, the beam failure recovery response onthe downlink control channel, wherein the random access preamblecorresponds to the selected reference signal.
 2. The method of claim 1,selecting of the reference signal further comprising: selecting thereference signal from among the at least one reference signal based on areference signal receiving power (RSRP) associated with the at least onereference signal.
 3. The method of claim 1, wherein each of the at leastone reference signal is one of synchronous signal (SS) block or channelstate information-reference signal (CSI-RS).
 4. A method performed by abase station in a wireless communication system, the method comprising:transmitting first information on at least one reference signal to beused for identifying one or more candidate beams associated with a beamfailure recovery request and second information on a search spaceassociated with a beam failure recovery response to a terminal;receiving, from the terminal a random access preamble for the beamfailure recovery request based on a reference signal among the at leastone reference signal, identified by the first information; andtransmitting the beam failure recovery response on a downlink controlchannel, wherein the downlink control channel is monitored for the beamfailure recovery response based on the search space identified by thesecond information, the downlink control channel being identified by acell radio network temporary identifier (C-RNTI), and the random accesspreamble corresponds to the reference signal.
 5. The method of claim 4,wherein the reference signal is selected from among the at least onereference signal based on a reference signal receiving power (RSRP)associated with the at least one reference signal.
 6. The method ofclaim 4, wherein each of the at least one reference signal is one ofsynchronous signal (SS) block or channel state information-referencesignal (CSI-RS).
 7. A terminal for receiving a beam failure recoveryresponse, the terminal comprising: a transceiver; and a processorcoupled with the transceiver and configured to: receive, from a basestation, first information including information on at least onereference signal to be used for identifying one or more candidate beamsassociated with a beam failure recovery request and second informationon a search space associated with a beam failure recovery response,select a reference signal based on the first information, transmit, tothe base station, a random access preamble for the beam failure recoveryrequest based on the selected reference signal, identify the searchspace, for monitoring a downlink control channel based on the secondinformation, the search space being used for the beam failure recoveryresponse, monitor the downlink control channel based on the identifiedsearch space, the downlink control channel being identified by a cellradio network temporary identifier (C-RNTI), and receive, from the basestation, the beam failure recovery response on the downlink controlchannel, wherein the random access preamble corresponds to the selectedreference signal.
 8. The terminal of claim 7, wherein the processor isfurther configured to selecting the reference signal from among the atleast one reference signal based on a reference signal receiving power(RSRP) associated with the at least one reference signal.
 9. Theterminal of claim 7, wherein each of the at least one reference signalis one of synchronous signal (SS) block or channel stateinformation-reference signal (CSI-RS).
 10. A base station fortransmitting a beam failure recovery response, the base stationcomprising: a transceiver; and a processor coupled with the transceiverand configured to: transmit first information on at least one referencesignal to be used for identifying one or more candidate beams associatedwith a beam failure recovery request and second information on a searchspace associated with a beam failure recovery response to a terminal,receive, from the terminal a random access preamble for the beam failurerecovery request based on a reference signal among the at least onereference signal, identified by the first information, and transmit thebeam failure recovery response on a downlink control channel, whereinthe downlink control channel is monitored for the beam failure recoveryresponse based on the search space identified by the second information,the downlink control channel being identified by a cell radio networktemporary identifier (C-RNTI) and the random access preamble correspondsto the reference signal.
 11. The base station of claim 10, wherein thereference signal is selected from among the at least one referencesignal based on a reference signal receiving power (RSRP) associatedwith the at least one reference signal.
 12. The base station of claim10, wherein each of the at least one reference signal is one ofsynchronous signal (SS) block or channel state information-referencesignal (CSI-RS).